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Showing papers in "Journal of Zhejiang University Science in 2006"


Journal ArticleDOI
TL;DR: This paper presents a simple and efficient clustering algorithm based on the k-means algorithm, which is easy to implement, requiring a simple data structure to keep some information in each iteration to be used in the next iteration.
Abstract: In k-means clustering, we are given a set of n data points in d-dimensional space ℝd and an integer k and the problem is to determine a set of k points in ℝd, called centers, so as to minimize the mean squared distance from each data point to its nearest center. In this paper, we present a simple and efficient clustering algorithm based on the k-means algorithm, which we call enhanced k-means algorithm. This algorithm is easy to implement, requiring a simple data structure to keep some information in each iteration to be used in the next iteration. Our experimental results demonstrated that our scheme can improve the computational speed of the k-means algorithm by the magnitude in the total number of distance calculations and the overall time of computation.

315 citations


Journal ArticleDOI
TL;DR: The computational study showed that the proposed algorithm is a feasible and effective approach for capacitated vehicle routing problem, especially for large scale problems.
Abstract: Capacitated vehicle routing problem (CVRP) is an NP-hard problem. For large-scale problems, it is quite difficult to achieve an optimal solution with traditional optimization methods due to the high computational complexity. A new hybrid ap- proximation algorithm is developed in this work to solve the problem. In the hybrid algorithm, discrete particle swarm optimiza- tion (DPSO) combines global search and local search to search for the optimal results and simulated annealing (SA) uses certain probability to avoid being trapped in a local optimum. The computational study showed that the proposed algorithm is a feasible and effective approach for capacitated vehicle routing problem, especially for large scale problems.

225 citations


Journal ArticleDOI
TL;DR: In this paper, the role of minimum quantity lubrication (MQL) by vegetable oil on cutting temperature, tool wear, surface roughness and dimensional deviation in turning AISI-1060 steel at industrial speed-feed combinations by uncoated carbide insert was investigated.
Abstract: In all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inherently produces high cutting temperature, which not only reduces tool life but also impairs the product quality. Metal cutting fluid changes the performance of machining operations because of their lubrication, cooling and chip flushing functions, but the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. The minimization of cutting fluid also leads to economical benefits by way of saving lubricant costs and workpiece/tool/machine cleaning cycle time. The concept of minimum quantity lubrication (MQL) has been suggested since a decade ago as a means of addressing the issues of environmental intrusiveness and occupational hazards associated with the airborne cutting fluid particles on factory shop floors. This paper deals with experimental investigation on the role of MQL by vegetable oil on cutting temperature, tool wear, surface roughness and dimensional deviation in turning AISI-1060 steel at industrial speed-feed combinations by uncoated carbide insert. The encouraging results include significant reduction in tool wear rate, dimensional inaccuracy and surface roughness by MQL mainly through reduction in the cutting zone temperature and favorable change in the chip-tool and work-tool interaction.

137 citations


Journal ArticleDOI
TL;DR: In this paper, double logistic regression is applied in the study area, which showed that elevation, proximity to road, river and residential area are main factors triggering landslide occurrence in this area.
Abstract: Landslide susceptibility map is one of the study fields portraying the spatial distribution of future slope failure susceptibility. This paper deals with past methods for producing landslide susceptibility map and divides these methods into 3 types. The logistic linear regression approach is further elaborated on by crosstabs methods, which is used to analyze the relationship between the categorical or binary response variable and one or more continuous or categorical or binary explanatory variables derived from samples. It is an objective assignment of coefficients serving as weights of various factors under considerations while expert opinions make great difference in heuristic approaches. Different from deterministic approach, it is very applicable to regional scale. In this study, double logistic regression is applied in the study area. The entire study area is first analyzed. The logistic regression equation showed that elevation, proximity to road, river and residential area are main factors triggering landslide occurrence in this area. The prediction accuracy of the first landslide susceptibility map was showed to be 80%. Along the road and residential area, almost all areas are in high landslide susceptibility zone. Some non-landslide areas are incorrectly divided into high and medium landslide susceptibility zone. In order to improve the status, a second logistic regression was done in high landslide susceptibility zone using landslide cells and non-landslide sample cells in this area. In the second logistic regression analysis, only engineering and geological conditions are important in these areas and are entered in the new logistic regression equation indicating that only areas with unstable engineering and geological conditions are prone to landslide during large scale engineering activity. Taking these two logistic regression results into account yields a new landslide susceptibility map. Double logistic regression analysis improved the non-landslide prediction accuracy. During calculation of parameters for logistic regression, landslide density is used to transform nominal variable to numeric variable and this avoids the creation of an excessively high number of dummy variables.

104 citations


Journal ArticleDOI
TL;DR: A variant of the Hill cipher that adjusts the encryption key to form a different key for each block encryption that yields higher security and significantly superior encryption quality compared to the original one.
Abstract: The Hill cipher algorithm is one of the symmetric key algorithms that have several advantages in data encryption. However, a main drawback of this algorithm is that it encrypts identical plaintext blocks to identical ciphertext blocks and cannot encrypt images that contain large areas of a single color. Thus, it does not hide all features of the image which reveals patterns in the plaintext. Moreover, it can be easily broken with a known plaintext attack revealing weak security. This paper presents a variant of the Hill cipher that overcomes these disadvantages. The proposed technique adjusts the encryption key to form a dif- ferent key for each block encryption. Visually and computationally, experimental results demonstrate that the proposed variant yields higher security and significantly superior encryption quality compared to the original one.

87 citations


Journal ArticleDOI
TL;DR: An overview of the history of scalable video coding, and a review of the video coding layer (VCL) and NAL of the latest SVC draft specification are given, which discusses different aspects of the draft SVC RTP payload format.
Abstract: The scalable extension of H.264/AVC, known as scalable video coding or SVC, is currently the main focus of the Joint Video Team's work. In its present working draft, the higher level syntax of SVC follows the design principles of H.264/AVC. Self-contained network abstraction layer units (NAL units) form natural entities for packetization. The SVC specification is by no means finalized yet, but nevertheless the work towards an optimized RTP payload format has already started. RFC 3984, the RTP payload specification for H.264/AVC has been taken as a starting point, but it became quickly clear that the scalable features of SVC require adaptation in at least the areas of capability/operation point signaling and documentation of the extended NAL unit header. This paper first gives an overview of the history of scalable video coding, and then reviews the video coding layer (VCL) and NAL of the latest SVC draft specification. Finally, it discusses different aspects of the draft SVC RTP payload format, in- cluding the design criteria, use cases, signaling and payload structure.

82 citations


Journal ArticleDOI
TL;DR: Methods are proposed for enhancing the converging velocity of the COA (chaos optimization algorithm) based on using carrier wave two times, which can greatly increase the speed and efficiency of the first carrier wave’s search for the optimal point in implementing the sophisticated searching during the second carrier wave.
Abstract: In this article, some methods are proposed for enhancing the converging velocity of the COA (chaos optimization algorithm) based on using carrier wave two times, which can greatly increase the speed and efficiency of the first carrier wave’s search for the optimal point in implementing the sophisticated searching during the second carrier wave is faster and more accurate. In addition, the concept of using the carrier wave three times is proposed and put into practice to tackle the multi-variables optimization problems, where the searching for the optimal point of the last several variables is frequently worse than the first several ones.

62 citations


Journal ArticleDOI
TL;DR: This work is aimed at investigating the online scheduling problem on two parallel and identical machines with a new feature that service requests from various customers are entitled to many different grade of service (GoS) levels, so each job and machine are labelled with the GoS levels.
Abstract: This work is aimed at investigating the online scheduling problem on two parallel and identical machines with a new feature that service requests from various customers are entitled to many different grade of service (GoS) levels, so each job and machine are labelled with the GoS levels, and each job can be processed by a particular machine only when its GoS level is no less than that of the machine. The goal is to minimize the makespan. For non-preemptive version, we propose an optimal online algorithm with competitive ratio 5/3. For preemptive version, we propose an optimal online algorithm with competitive ratio 3/2.

61 citations


Journal ArticleDOI
TL;DR: Performance results concerning flexibility, video quality and delay of the system are presented, demonstrating that scalable coding outperforms existing state-of-the-art systems and offers the right platform for building next-generation multipoint videoconferencing systems.
Abstract: We describe a system for multipoint videoconferencing that offers extremely low end-to-end delay, low cost and complexity, and high scalability, alongside standard features associated with high-end solutions such as rate matching and per- sonal video layout. The system accommodates heterogeneous receivers and networks based on the Internet Protocol and relies on scalable video coding to provide a coded representation of a source video signal at multiple temporal and spatial resolutions as well as quality levels. These are represented by distinct bitstream components which are created at each end-user encoder. Depending on the specific conferencing environment, some or all of these components are transmitted to a Scalable Video Conferencing Server (SVCS). The SVCS redirects these components to one or more recipients depending on, e.g., the available network con- ditions and user preferences. The scalable aspect of the video coding technique allows the system to adapt to different network conditions, and also accommodates different end-user requirements (e.g., a user may elect to view another user at a high or low spatial resolution). Performance results concerning flexibility, video quality and delay of the system are presented using the Joint Scalable Video Model (JSVM) of the forthcoming SVC (H.264 Annex G) standard, demonstrating that scalable coding outper- forms existing state-of-the-art systems and offers the right platform for building next-generation multipoint videoconferencing systems.

56 citations


Journal ArticleDOI
TL;DR: This paper provides robust and effective error concealment techniques for SVC with spatial scalability and shows that the proposed methods provide substantial improvement, both subjectively and objectively, without a significant complexity overhead.
Abstract: Scalable video coding (SVC), as the Scalable Extension of H.264/AVC, is an ongoing international video coding standard designed for network adaptive or device adaptive applications and also offers high coding efficiency. However, packet losses often occur over unreliable networks even for base layer of SVC and have severe impact on the playback quality of compressed video. Until now, no literature has discussed error concealment support for standard SVC bit-stream. In this paper, we provide robust and effective error concealment techniques for SVC with spatial scalability. Experimental results showed that the proposed methods provide substantial improvement, both subjectively and objectively, without a significant complexity overhead.

55 citations


Journal ArticleDOI
TL;DR: The authors propose a scheme for Systematic Lossy Error Protection (SLEP) of an H.264/AVC compressed video bit stream, using standard compatible features such as redundant slices, and flexible macroblock ordering, and demonstrate the advantages of SLEP over forward error correction (FEC) as an error resilience scheme.
Abstract: The authors propose a scheme for Systematic Lossy Error Protection (SLEP) of an H.264/AVC compressed video bit stream, using standard compatible features such as redundant slices, and flexible macroblock ordering. The systematic portion consists of a conventional H.264/AVC bit stream. For error resilience, an additional Wyner-Ziv bit stream is also transmitted. The Wyner-Ziv bit stream allows the decoding of a coarsely quantized description of the original video signal, and is efficiently gen- erated by using H.264/AVC redundant slices in conjunction with Reed-Solomon coding. The Wyner-Ziv bit stream is decoded in order to recover the redundant video descriptions, which are used in lieu of portions lost from the original video signal due to channel errors. SLEP allows the video quality to degrade gracefully with worsening channel conditions, and provides a flexible trade-off between the achieved error resilience and the coarseness of the redundant description. The performance can be improved especially for low motion video sequences, by applying SLEP to a region-of-interest in the video frame, using flexible macroblock ordering (FMO). Experimental results provided for two video transmission scenarios, demonstrate the advantages of SLEP over forward error correction (FEC) as an error resilience scheme.

Journal ArticleDOI
TL;DR: In this paper, the influence of preload level on flexural behavior of reinforced concrete beams, including 16 beams strengthened with CFRP laminate at different levels of pre-load and 2 control beams, were tested to investigate the influence on the flexural behaviour of CFRP-strengthened RC beam.
Abstract: Eighteen reinforced concrete beams, including 16 beams strengthened with CFRP laminate at different levels of preload and 2 control beams, were tested to investigate the influence of preload level on flexural behavior of CFRP-strengthened RC beam. The experimental parameters include rebar ratios, number of plies of CFRP laminates and preload level at the time of strengthening. Theoretical analysis was also carried out to explain the experimental phenomena and results. The experimental and theoretical results indicated that the preload level has more influence on the stiffness and deflection of the strengthened beam, both at post-cracking and post-yielding stage, than that on the yielding and ultimate flexural strength of the strengthened beam. The main failure mode of CFRP-strengthened beam is the intermediate crack-induced debonding of CFRP laminates, provided that the development length of CFRP laminates and shear capacity of the beam are sufficient.

Journal ArticleDOI
TL;DR: In this article, the experimental evaluation of thermal performance of a packed bed latent heat TES unit integrated with solar flat plate collector is presented, which contains paraffin as phase change material (PCM) filled in spherical capsules, which are packed in an insulated cylindrical storage tank.
Abstract: In thermal systems such as solar thermal and waste heat recovery systems, the available energy supply does not usually coincide in time with the process demand. Hence some form of thermal energy storage (TES) is necessary for the most effective utilization of the energy source. This study deals with the experimental evaluation of thermal performance of a packed bed latent heat TES unit integrated with solar flat plate collector. The TES unit contains paraffin as phase change material (PCM) filled in spherical capsules, which are packed in an insulated cylindrical storage tank. The water used as heat transfer fluid (HTF) to transfer heat from the solar collector to the storage tank also acts as sensible heat storage material. Charging experiments were carried out at varying inlet fluid temperatures to examine the effects of porosity and HTF flow rate on the storage unit performance. The performance parameters such as instantaneous heat stored, cumulative heat stored, charging rate and system efficiency are studied. Discharging experiments were carried out by both continuous and batchwise processes to recover the stored heat, and the results are presented.

Journal ArticleDOI
TL;DR: A novel method for transporting multi-view videos that aims to keep the bandwidth requirements on both end-users and servers as low as possible and the performance of the approach was studied through network experiments.
Abstract: The authors propose a novel method for transporting multi-view videos that aims to keep the bandwidth requirements on both end-users and servers as low as possible The method is based on application layer multicast, where each end point receives only a selected number of views required for rendering video from its current viewpoint at any given time The set of selected videos changes in real time as the user’s viewpoint changes because of head or eye movements Techniques for reducing the black-outs during fast viewpoint changes were investigated The performance of the approach was studied through network experiments

Journal ArticleDOI
TL;DR: In this paper, the authors examined the possibility of extending the concept of double negative electromagnetic wave media to acoustic waves and showed that acoustic metamaterials require both the effective density and bulk modulus to be simultaneously negative in the sense of an effective medium.
Abstract: The realization of double negative electromagnetic wave media, sometimes called left-handed materials (LHMs) or metamaterials, have drawn considerable attention in the past few years. We will examine the possibility of extending the concept to acoustic waves. We will see that acoustic metamaterials require both the effective density and bulk modulus to be simultaneously negative in the sense of an effective medium. If we can find a double negative (negative density and bulk modulus) acoustic medium, it will be an acoustic analogue of Veselago’s medium in electromagnetism, and share many novel consequences such as negative refractive index and backward wave characteristics. We will give one example of such a medium.

Journal ArticleDOI
TL;DR: To determine the mechanism of the resistance, CYP51 gene was amplified from P. digitatum genome and sequenced, and revealed that a tandem repeat of four extra copies of a unique 126-bp sequence in the upstream promoter region of CYP 51 gene present only in imazalil-R isolates, but not inImazalIL-S isolate, implying this tandem repeat sequence may regulate the expression of CyP51 positively, and lead to the sensitivity decrease.
Abstract: Green mold caused by Penicillium digitatum (Pers.:Fr) Sacc. is one of the most important postharvest diseases of citrus fruits. Experiments were conducted to determine the occurrence of resistance of P. digitatum to imazalil in China. Four imazalil-Resistant (R) isolates were identified from 189 isolates of P. digitatum. The highest EC50 of an imazalil-R isolate was 0.578 mg/L, 29 times higher than that of the most imazalil-sensitive (S) isolate, suggesting that imazalil-R biotype of P. digtatum had occurred in China. In vitro assessment indicated that the imazalil-R isolates were not significantly different from imazalil-S isolates in their growth rate and sporulation, indicating that the imazalil-R biotype has competence similar to that of imazalil-S one and could co-exist with it in environment. To determine the mechanism of the resistance, CYP51 gene was amplified from P. digitatum genome and sequenced. The results revealed that a tandem repeat of four extra copies of a unique 126-bp sequence in the upstream promoter region of CYP51 gene present only in imazalil-R isolates, but not in imazalil-S isolates, implying this tandem repeat sequence may regulate the expression of CYP51 positively, and lead to the sensitivity decrease.

Journal ArticleDOI
TL;DR: In this paper, a metamaterial was introduced into the cover of a patch antenna and its band structure was analyzed, which works like a lens and could effectively improve the patch antenna's directivity.
Abstract: A metamaterial was introduced into the cover of a patch antenna and its band structure was analyzed. The metamaterial cover with correct selection of the working frequency increases by 9.14 dB the patch antenna’s directivity. The mechanism of metamaterial cover is completely different from that of a photonic bandgap cover. The mechanism of the metamaterial cover, the number of the cover’s layers, and the distance between the layers, were analyzed in detail. The results showed that the metamaterial cover, which works like a lens, could effectively improve the patch antenna’s directivity. The physical reasons for the improvement are also given.

Journal ArticleDOI
TL;DR: In this article, the improved control schemes of two typical traditional vector control schemes used in DFIG were proposed, and simulation study of the proposed and traditional control schemes, with robust rotor current control using Internal Model Control (IMC) method, was carried out.
Abstract: Doubly-Fed Induction Generator (DFIG), with vector control applied, is widely used in Variable-Speed Constant-Frequency (VSCF) wind energy generation system and shows good performance in maximum wind energy capture. But in two traditional vector control schemes, the equivalent stator magnetizing current is considered invariant in order to simplify the rotor current inner-loop controller. The two schemes can perform very well when the grid is in normal condition. However, when grid disturbance such as grid voltage dip or swell fault occurs, the control performance worsens, the rotor over current occurs and the Fault Ride-Through (FRT) capability of the DFIG wind energy generation system gets seriously deteriorated. An accurate DFIG model was used to deeply investigate the deficiency of the traditional vector control. The improved control schemes of two typical traditional vector control schemes used in DFIG were proposed, and simulation study of the proposed and traditional control schemes, with robust rotor current control using Internal Model Control (IMC) method, was carried out. The validity of the proposed modified schemes to control the rotor current and to improve the FRT capability of the DFIG wind energy generation system was proved by the comparison study.

Journal ArticleDOI
TL;DR: In this paper, the authors formulate a "Moore's law" for photonic integrated circuits (PICs) and their spatial integration density using two methods: decomposing the integrated photonics devices of diverse types into equivalent basic elements, which makes a comparison with the generic elements of electronic integrated circuits more meaningful.
Abstract: We formulate a “Moore’s law” for photonic integrated circuits (PICs) and their spatial integration density using two methods. One is decomposing the integrated photonics devices of diverse types into equivalent basic elements, which makes a comparison with the generic elements of electronic integrated circuits more meaningful. The other is making a complex component equivalent to a series of basic elements of the same functionality, which is used to calculate the integration density for functional components realized with different structures. The results serve as a benchmark of the evolution of PICs and we can conclude that the density of integration measured in this way roughly increases by a factor of 2 per year. The prospects for a continued increase of spatial integration density are discussed.

Journal ArticleDOI
TL;DR: This work studies the trade-off between the selfish motive of minimizing video distortion and the global good of minimizing network congestions in a convex optimization formulation, and discusses both centralized and distributed solutions for joint routing and rate allocation for multiple streams.
Abstract: The support for multiple video streams in an ad-hoc wireless network requires appropriate routing and rate allocation measures ascertaining the set of links for transmitting each stream and the encoding rate of the video to be delivered over the chosen links. The routing and rate allocation procedures impact the sustained quality of each video stream measured as the mean squared error (MSE) distortion at the receiver, and the overall network congestion in terms of queuing delay per link. We study the trade-off between these two competing objectives in a convex optimization formulation, and discuss both centralized and dis- tributed solutions for joint routing and rate allocation for multiple streams. For each stream, the optimal allocated rate strikes a balance between the selfish motive of minimizing video distortion and the global good of minimizing network congestions, while the routes are chosen over the least-congested links in the network. In addition to detailed analysis, network simulation results using ns-2 are presented for studying the optimal choice of parameters and to confirm the effectiveness of the proposed measures.

Journal ArticleDOI
TL;DR: This work proposed an extended Web service QoS model based on configurable fuzzy synthetic evaluation system, which takes QoS as a key factor when choosing from functionally equivalent services.
Abstract: Quality of Service (QoS) is a key factor in Web service advertising, choosing and runtime monitoring. Web service QoS is multi-faceted, fuzzy and dynamic. Current researches focus on implementation level performance assurance, ignoring domain specific or application level metrics which are also very important to service users. Industry Web service standards lack QoS expression. The support for QoS based service choice-making is very limited. We proposed an extended Web service QoS model based on configurable fuzzy synthetic evaluation system. Web service QoS is evaluated dynamically according to the service context. A QoS requirement description model is also given for service QoS requirement definition. An interactive Web service choice-making process is described, which takes QoS as a key factor when choosing from functionally equivalent services.

Journal ArticleDOI
TL;DR: The mode of viral infection, and the activity of certain antiviral proteins involved in silkworm immunity and also in some other insects are discussed and will be helpful in understanding the molecular aspects of antiviral immunity, disease control and may form the basis for potential use of silkworm in other fields such as medicine.
Abstract: The silkworm Bombyx mori is exploited both as a powerful biological model system and also as a tool to convert leaf protein into silk. Silkworm larvae often suffer from viral infections causing heavy losses to the economy of the silk industry. Insects exhibit both humoral and cellular immune responses that are effective against various pathogens like bacteria, fungi, protozoa, etc., but no insect immune response is effective against viral infections. To date, no satisfactory reports are available on antiviral immunity of the silkworm. Some efforts have been made by very few workers to identify and characterize the antiviral proteins in the silkworm. In the present article the mode of viral infection, and the activity of certain antiviral proteins involved in silkworm immunity and also in some other insects are discussed. The investigation will be helpful in understanding the molecular aspects of antiviral immunity, disease control and may form the basis for potential use of silkworm in other fields such as medicine.

Journal ArticleDOI
TL;DR: This paper uses HTTP for transport and argues that these two components are sufficient for specifying an open streaming architecture based on the MPEG-4 file format and compares to 3GPP PSS Rel-6 adaptive streaming when appropriate.
Abstract: In this paper we describe how progressive download and adaptive streaming can be combined into a simple and efficient streaming framework. Based on the MPEG-4 file format (MP4) we use HTTP for transport and argue that these two components are sufficient for specifying an open streaming architecture. The client selects appropriate chunks from the MP4 file to be transferred based on (1) the header information (i.e. the “moov” box) in the first part of the file and (2) his observation of network throughput. The framework is completely client driven which allows for better server scalability and reduces signalling overhead. We discuss architecture and implementation issues such as complexity, interoperability and scalability and compare to 3GPP PSS Rel-6 adaptive streaming when appropriate. Measurements from a simple MP4/HTTP streaming client are presented showing that appropriate chunks are selected such that increased reliability is achieved.

Journal ArticleDOI
TL;DR: In this paper, the effects of different track geometrical parameters on the vertical and lateral wear by conducting a three phase field investigation were analyzed and recommendations for prevention or reduction of rail wear are presented.
Abstract: Rail wear has dramatic impact on track performance, ride quality and maintenance costs. The amount of rail wear is influenced by various elements among which geometric parameters play an important role. The amount of wear in Iran’s railway lines and its imposed maintenance costs oblige us to make modifications on the various geometrical parameters. In order to ensure the effectiveness of these changes, it is necessary to investigate these parameters and their effects on the wear. This research is aimed at studying the effects of different track geometrical parameters on the vertical and lateral wear by conducting a three phase field investigation. The first phase was carried out at the switches of a station, the second phase at a straight line, and the third at a curved line out of the station. The results obtained are analyzed and the role of each track geometrical parameter in the rail wear is discussed. Recommendations for prevention or reduction of rail wear are presented.

Journal ArticleDOI
TL;DR: In this article, chemical coagulation was used to remove the compounds present in wastewater from dye manufacturing industry and the results showed that high extent of Fe(III) hydrolysis was not always suited for chemical oxygen demand (COD) removal in our wastewater, that electrostatic interaction between flocs and organic contaminants played an important role in removal of organic contaminants.
Abstract: Chemical coagulation was used to remove the compounds present in wastewater from dye manufacturing industry. The character of wastewater was determined. Most compounds found in the wastewater are phenol derivatives, aniline derivatives, organic acid and benzene derivatives, output from dye manufacturing. Various polyferric chloride coagulants were investigated. Results showed that high extent of Fe(III) hydrolysis was not always suited for chemical oxygen demand (COD) removal in our wastewater, that electrostatic interaction between flocs and organic contaminants played an important role in removal of organic contaminants, that copolymers of Al(III), Si(IV) and Fe(III) were helpful for high flocculating effect, that COD removal efficiency of poly-silicate-aluminium-ferric chloride (PSAFC) and polyferric chloride (PFC) coagulant increased with increasing dose of coagulants, and that the performance of PSAFC and PFC coagulants was superior to PAC coagulant. This difference in efficiency may also be attributed to the copolymers of Si(IV), Al(III) and Fe(III). However, compared with PFC, PSAFC can easily reach high COD removal efficiency below coagulant dose 0.3 g/L. Thus, from the economic point of view, PSAFC is more suitable for treatment of wastewater effluent from dye manufacturing.

Journal ArticleDOI
TL;DR: Alternative techniques such as robust source coding and channel coding techniques (ARQ: automatic repeat request, FEC: forward error correction) are presented; their integration into the proposed framework is also discussed.
Abstract: Standard-compatible multiple description coding (MDC) and layered coding (LC) are efficient ways to ensure erasure resilient, scalable transmission of encoded multimedia sources via RTP, allowing a gradual degradation of the application quality with increasing packet loss rate and decreasing bandwidth/throughput on the network. In this paper we review the stan- dard-compatible framework proposed to IETF. Alternative techniques such as robust source coding and channel coding techniques (ARQ: automatic repeat request, FEC: forward error correction) are presented; their integration into the proposed framework is also discussed. The performances of MDC and LC either coupled with channel coding or not, are summarized by reference to current literature. Typical cases and examples are illustrated.

Journal ArticleDOI
TL;DR: In this article, a matrix inversion Normalized Least Mean Square (MI-NLMS) adaptive beamforming algorithm was developed for smart antenna application, which combined the individual good aspects of SMI and NLMS algorithms.
Abstract: A Matrix Inversion Normalized Least Mean Square (MI-NLMS) adaptive beamforming algorithm was developed for smart antenna application. The MI-NLMS which combined the individual good aspects of Sample Matrix Inversion (SMI) and the Normalized Least Mean Square (NLMS) algorithms is described. Simulation results showed that the less complexity MI-NLMS yields 15 dB improvements in interference suppression and 5 dB gain enhancement over LMS algorithm, converges from the initial iteration and achieves 24% BER improvements at cochannel interference equal to 5. For the case of 4-element uniform linear array antenna, MI-NLMS achieved 76% BER reduction over LMS algorithm.

Journal ArticleDOI
Yang Shufeng1, LI Zi-long1, Chen Han-lin1, Chen Wen, Yu Xing1 
TL;DR: In this article, 40Ar-39Ar age dating for basaltic samples from the Yingan section, Keping area and Damusi section of the southwestern part of Tarim Basin was reported.
Abstract: This paper reports 40Ar-39Ar ages of northwestern China’s Tarim Basin Permian basalts. 40Ar-39Ar age dating for basaltic samples from the Yingan section, Keping area and Damusi section of the southwestern part of Tarim Basin yields plateau ages of (281.8±4.2) Ma and a weighted mean value of (290.1±3.5) Ma respectively. This study combined with previous data indicates that the basaltic rocks from the studied area formed during 282∼290 Ma. 40Ar-39Ar age dating from the basalts addresses a tectonothermal event in the Tarim Basin that occurred during the Early Permian of 278∼290 Ma.

Journal ArticleDOI
TL;DR: An analytic model to describe these impairments without the reference of the original video (NR) is developed and an impairment metric based on the model is proposed, which takes into account both impairment length and impairment strength.
Abstract: Video compression technologies are essential in video streaming application because they could save a great amount of network resources. However compressed videos are also extremely sensitive to packet loss which is inevitable in today's best effort IP network. Therefore we think accurate evaluation of packet loss impairment on compressed video is very important. In this work, we develop an analytic model to describe these impairments without the reference of the original video (NR) and propose an impairment metric based on the model, which takes into account both impairment length and impairment strength. To evaluate an impaired frame or video, we design a detection and evaluation algorithm (DE algorithm) to compute the above metric value. The DE algorithm has low computational complexity and is currently being implemented in the real-time monitoring module of our HDTV over IP system. The impairment metric and DE algorithm could also be used in adaptive system or be used to compare different error concealment strategies.

Journal ArticleDOI
TL;DR: In this article, the authors studied the warm-hot deformation behavior of 20CrMnTi steel with hot compression tests at temperature range of 1123∼1273 K and strain rate of 0.1∼20 s−1.
Abstract: The warm-hot deformation behavior of 20CrMnTi steel was studied with hot compression tests at temperature range of 1123∼1273 K and strain rate of 0.1∼20 s−1. The activation energy for warm-hot deformation is 426.064 KJ/mol. The influences of Zener-Hollomon parameter, strain and grain size imposing on the flow stress were analyzed in the temperature range of warm-hot forging. Creep theory and methematical theory of statistics were used to obtain mathematical models of flow stress. The research and results provide scientific basis for controlling microstructure of forging process through Zener-Hollomon parameter.